You’ve probably heard someone joke and say that they are allergic to exercise out of the mere cost of being funny and probably lazy. However, there is in fact a real allergy that makes some allergic to exercising. Only 1,000 people are said to have the allergy. Called exercise-induced anaphylaxis, this allergy is only noticed after someone eats a certain type of food, say peanuts, and goes to exercise. That person can easily eat peanuts without having a reaction, but when exercise is added, the person may experience fainting, vomiting and difficulty breathing.